Managing HP Serviceguard for Linux, Eighth Edition, March 2008

Planning and Documenting an HA Cluster
General Planning
Chapter 494
General Planning
A clear understanding of your high availability objectives will quickly
help you to define your hardware requirements and design your system.
Use the following questions as a guide for general planning:
1. What applications must continue to be available in the event of a
failure?
2. What system resources (processing power, networking, SPU, memory,
disk space) are needed to support these applications?
3. How will these resources be distributed among the nodes in the
cluster during normal operation?
4. How will these resources be distributed among the nodes of the
cluster in all possible combinations of failures, especially node
failures?
5. How will resources be distributed during routine maintenance of the
cluster?
6. What are the networking requirements? Are all networks and
subnets available?
7. Have you eliminated all single points of failure? For example:
• network points of failure.
• disk points of failure.
• electrical points of failure.
• application points of failure.
Serviceguard Memory Requirements
Serviceguard requires approximately 15.5 MB of lockable memory.
Planning for Expansion
When you first set up the cluster, you indicate a set of nodes and define a
group of packages for the initial configuration. At a later time, you may
wish to add additional nodes and packages, or you may wish to use